Problem: Solve the following expression and give your answer as a fraction. $ 0.13 \times \dfrac{21}{50} \times -\dfrac{17}{25} = {?} $
First get all of the numbers as simplified fractions. $ 0.13 = \dfrac{1}{10} = \dfrac{13}{100} $ Now we have: $ \dfrac{13}{100} \times \dfrac{21}{50} \times -\dfrac{17}{25} = {?} $ $ \phantom{ \dfrac{13}{100} \times \dfrac{21}{50} \times -\dfrac{17}{25}} = \dfrac{13 \times 21 \times -17} {100 \times 50 \times 25} $ $ \phantom{ \dfrac{13}{100} \times \dfrac{21}{50} \times -\dfrac{17}{25}} = -\dfrac{4641}{125000} $